Assessing impact of saline intrusion on rice cultivating area in Ke Sach district, Soc Trang province, Vietnam

Abstract

This study was carried out to evaluate the effects of saline intrusion on agricultural activities, thereby proposing adaptation and mitigation measures for local people. Salinity was measured at 15 locations on the main and tributary rivers in Ke Sach district, Soc Trang province, Vietnam from January to September 2020. The method of direct interview with farmers was used to evaluate the knowledge and effects of saline intrusion on agricultural production. Salinity measurement results showed that salinity intrusion oc-curred and lasted from February to the end of May during the dry season (the Winter-Spring rice crop). During the rainy season (June-September), due to the large amount of water, salinity was only be-tween 0.01 and 0.1‰. However, the research has found significant effects in the Summer-Autumn rice crop due to the accumulation of salinity in the soil from the Winter-Spring rice crop, which reduces the rice yield by 10-30%. The interview results revealed that more than 80% of the farmers were aware of the effects of saline water intrusion. Local authorities also regularly organize seminars to disseminate basic knowledge to the community to minimize the risks and impacts of saltwater intrusion. The proposed temporary solutions include rainwater storage, maintenance of saline prevention sluices, construction of more water regulation canals, financial support, and strengthening of salinity monitoring stations. In order to adapt to the long-term salinity conditions, local authorities need to focus on researching changing cropping patterns, crop structure, using new rice varieties that are able to adapt to drought and salty conditions. Besides, there will be technical assistance, capital for people to adapt well to the saline intrusion situation.

Seasonal Variation and Key Variables Affecting Surface Water Quality in North Vam Nao Area, Vietnam

“…According to [26,33], dissolved oxygen in water depends on temperature, decomposition processes of organic compounds and photosynthesis of aquatic plants. When DO concentration is too low, it is a favorable condition to generate odor-causing H2S and reduce the self-cleaning ability of water bodies [24,34]. Compared with DO at the sampling sites on Tien and Hau rivers outside the full-dike area (5.14-5.44 mg/L) [26], DO levels in the current study were low.…”

“…The high TSS concentration not only has a strong impact on human activities and aquatic life in that area, but can also transport pollutants such as microorganisms, pesticides, etc. to other water bodies [34,35]. In addition, TSS also causes difficulties and increases costs for water treatment [34].…”

“…to other water bodies [34,35]. In addition, TSS also causes difficulties and increases costs for water treatment [34].…”

“…The results of PCA show that PC1 is the most important factor (47.10%) contributed by temperature, DO, BOD, COD, NH4 + -N and PO4 3− -P. This source of pollution has the characteristics of domestic and agricultural waste [17,20,21,52]. Temperature is directly affected by the characteristics of the water body and the disturbance process [34]. PC2 also significantly explains the variation (27.30%) of water quality in the rainy season with moderate contribution of pH (−0.501) and weak contribution of TSS (−0.403), NO3 − -N (0.383) and PO4 3− -P (0.320).…”

Salinity of Soil and Irrigation Water on Rice Productivity in the Canton of San Jacinto De Yaguachi, Ecuador

“…The above observations suggest that the rice plant behaves as moderately tolerant to salinity in the conditions of the canton of San Jacinto de Yaguachi. Giao (2021) found a reduction of up to 30 % in the average yield of different rice varieties when soil salinity reached a value of 3.87 % (approximately 6 dS m -1 ) due to…”